Abstract

Saturation discrimination is assumed to be dependent on the ratio of chromatic to achromatic components in the sensory response to a given wavelength. The usual methods of measurement do not, however, permit independent control of the chromatic and achromatic variables. On the basis of an opponent-colors theory of vision, a method is described for measuring directly and separately the spectral distributions of the chromatic components. A series of experiments is reported in which this method was used to obtain measures of the paired chromatic responses associated with the four primary spectral hues. Results are reported for two observers, 1° foveal test field, for an equal brightness spectrum (10 mL), and a neutral state of adaptation (10 mL). The measured chromatic responses, together with achromatic (luminosity) functions measured earlier for the same observers, are used to predict the form of the spectral saturation discrimination function.

Two other experiments of a similar nature have been reported [L. Goldytsch, Z. Biol. 67, 35 (1917); E. Brücke and N. Inouye, Pflüger's Arch. ges. Physiol. 141, 573 (1911)]. In one, only a single chromatic response function (yellow) was measured, in the other, chromatic valence curves were determined for a color-blind observer.

L. M. Hurvich and D. Jameson, J. Opt. Soc. Am. 43, 485 (1953).

D. Jameson and L. M. Hurvich, J. Exptl. Psychol. 41, 455 (1951).

The phrase "chromatic valences" as used here is not to be confused with Hering's "optical valences" which refer to stimulus properties or capacities relative to a single, fixed state of adaptation (reference 26). Nor should the phrase "chromatic response" be confused with the so-called "fundamental response curves" or receptor sensitivity curves.

Two other experiments of a similar nature have been reported [L. Goldytsch, Z. Biol. 67, 35 (1917); E. Brücke and N. Inouye, Pflüger's Arch. ges. Physiol. 141, 573 (1911)]. In one, only a single chromatic response function (yellow) was measured, in the other, chromatic valence curves were determined for a color-blind observer.

L. M. Hurvich and D. Jameson, J. Opt. Soc. Am. 43, 485 (1953).

D. Jameson and L. M. Hurvich, J. Exptl. Psychol. 41, 455 (1951).

The phrase "chromatic valences" as used here is not to be confused with Hering's "optical valences" which refer to stimulus properties or capacities relative to a single, fixed state of adaptation (reference 26). Nor should the phrase "chromatic response" be confused with the so-called "fundamental response curves" or receptor sensitivity curves.